Spent lithium ion battery (LIB) recycle from electric vehicles: A mini-review

A review of new technologies for lithium-ion battery treatment

Lithium-ion batteries (LIBs) are widely used in various aspects of human life and production due to their safety, convenience, and low cost, especially in the field of electric vehicles (EVs). Currently, the number of LIBs worldwide is growing exponentially, which also leads to an increase in discarded LIBs. Spent lithium-ion batteries (S-LIBs) contain valuable metals and environmentally hazardous chemicals, necessitating proper resource recovery and harmless treatment of these S-LIBs. Therefore, research on S-LIBs recycling is beneficial for sustainable EVs development. This paper aims to critically review the research progress in the field of S-LIBs recycling, focusing on the recycling technology of cathode materials. First, the article introduces the composition, classification, and working principle of LIB. It then discusses the evaluation and monitoring of batteries that can no longer be used, so that they can be repurposed or dismantled for disposal. Subsequently, introduces that batteries that can no longer be used should undergo evaluation and monitoring for repurposing or dismantling. Emphasize the treatment of cathode materials, including two traditional recycling methods hydrometallurgy and pyrometallurgy as well as five new direct regeneration technologies and the application of cathode materials in non-battery fields. This work is expected to systematically demonstrate the treatment of S-LIBs and is of great significance for the sustainable EVs development of the LIB industry.

Conversion and fate of waste Li-ion battery electrolyte in a two-stage thermal treatment process

Disposal of electrolytes from waste lithium-ion batteries (LIBs) has gained much more attention with the growing application of LIBs, yet handling spent electrolyte is challengeable due to its high toxicity and the lack of established methods. In this study, a novel two-stage thermal process was developed for treating residual electrolytes resulted from spent lithium-ion batteries. The conversion of fluorophosphate and organic matter in oily electrolyte during low-temperature rotation distillation was investigated. The distribution and migration of the concentrated electrolytes were studied and the corresponding reaction mechanisms were elucidated. Additionally, the influence of alkali on the fixation of fluorine and phosphate was further examined. The results indicated that hydrolyzed carbonate esters and lithium in the electrolyte could combine to form Li2CO3 and the hydrolysable hexafluorophosphate was proven to be stable in the concentrated electrolyte (45 rpm/85 °C, 30 min). It was found that CO2, CO, CH4, and H2 were the primary pyrolysis gases, while the pyrolysis oil consisted of extremely flammable substances formed by the dissociation and recombination of chemical bonds in the electrolyte solvent. After pyrolysis at 300 °C, fluorine and phosphate were present in the form of sodium fluoride and sodium phosphate. The stability of the residue was enhanced, and the environmental risk was reduced. By adding alkali (KOH/Ca(OH)2, 20 %), hexafluorophosphate in the electrolyte was transformed into fluoride and phosphate in the residue, thereby reducing the device's corrosion from fluorine-containing gas. This study provides a viable approach for managing the residual electrolyte in the waste lithium battery recovery process.

Preoxidation and Prilling Combined with Doping Strategy to Build High-Performance Recycling Spent LiFePO4 Materials

Direct regeneration has gained much attention in LiFePO4 battery recycling due to its simplicity, ecofriendliness, and cost savings. However, the excess carbon residues from binder decomposition, conductive carbon, and coated carbon in spent LiFePO4 impair electrochemical performance of direct regenerated LiFePO4. Herein, we report a preoxidation and prilling collaborative doping strategy to restore spent LiFePO4 by direct regeneration. The excess carbon is effectively removed by preoxidation. At the same time, prilling not only reduces the size of the primary particles and shortens the diffusion distance of Li+ but also improves the tap density of the regenerated materials. Besides, the Li+ transmission of the regenerated LiFePO4 is further improved by Ti4+ doping. Compared with commercial LiFePO4, it has excellent low-temperature performance. The collaborative strategy provides a new insight into regenerating high-performance spent LiFePO4.

Toward Direct Regeneration of Spent Lithium-Ion Batteries: A Next-Generation Recycling Method

The popularity of portable electronic devices and electric vehicles has led to the drastically increasing consumption of lithium-ion batteries recently, raising concerns about the disposal and recycling of spent lithium-ion batteries. However, the recycling rate of lithium-ion batteries worldwide at present is extremely low. Many factors limit the promotion of the battery recycling rate: outdated recycling technology is the most critical one. Existing metallurgy-based recycling methods rely on continuous decomposition and extraction steps with high-temperature roasting/acid leaching processes and many chemical reagents. These methods are tedious with worse economic feasibility, and the recycling products are mostly alloys or salts, which can only be used as precursors. To simplify the process and improve the economic benefits, novel recycling methods are in urgent demand, and direct recycling/regeneration is therefore proposed as a next-generation method. Herein, a comprehensive review of the origin, current status, and prospect of direct recycling methods is provided. We have systematically analyzed current recycling methods and summarized their limitations, pointing out the necessity of developing direct recycling methods. A detailed analysis for discussions of the advantages, limitations, and obstacles is conducted. Guidance for future direct recycling methods toward large-scale industrialization as well as green and efficient recycling systems is also provided.

Recovery of metal ion resources from waste lithium batteries by in situ electro-leaching coupled with electrochemically switched ion exchange

A new green pathway of in situ electro-leaching coupled with electrochemically switched ion exchange (EL-ESIX) technology was developed for the separation and recovery of valuable metal ions from waste lithium batteries. By using the in situ electro-leaching, the leaching rates of Li+ and Co2+ from the prepared LiCoO2 film electrodes reached 100 % and 93.30 %, respectively, under the combined effect of the acidic microenvironment formed by the anodic electrolytic water and electrostatic repulsion. Subsequently, the Li+ in the electrolyte was further extracted by an electrochemically switched ion exchange (ESIX) process using LiMn2O4 as the film electrode, and Li+ was further enriched in the eluate by a cyclic adsorption and desorption process. The results indicate that the in situ electro-leaching has significant advantages over powder leaching, and for the recycling of waste lithium batteries, the final lithium recovery rate reached 94.51 % by using this in situ EL-ESIX technology.

Selective recycling of lithium from spent LiNixCoyMn1-x-yO2 cathode via constructing a synergistic leaching environment

The global response to lithium scarcity is overstretched, and it is imperative to explore a green process to sustainably and selectively recover lithium from spent lithium-ion battery (LIB) cathodes. This work investigates the distinct leaching behaviors between lithium and transition metals in pure formic acid and the auxiliary effect of acetic acid as a solvent in the leaching reaction. A formic acid-acetic acid (FA-AA) synergistic system was constructed to selectively recycle 96.81% of lithium from spent LIB cathodes by regulating the conditions of the reaction environment to inhibit the leaching of non-target metals. Meanwhile, the transition metals generate carboxylate precipitates enriched in the leaching residue. The inhibition mechanism of manganese leaching by acetic acid and the leaching behavior of nickel or cobalt being precipitated after release was revealed by characterizations such as XPS, SEM, and FTIR. After the reaction, 90.50% of the acid can be recycled by distillation, and small amounts of the residual Li-containing concentrated solution are converted to battery-grade lithium carbonate by roasting and washing (91.62% recovery rate). This recycling process possesses four significant advantages: i) no additional chemicals are required, ii) the lithium sinking step is eliminated, iii) no waste liquid is discharged, and iv) there is the potential for profitability. Overall, this study provides a novel approach to the waste management technology of lithium batteries and sustainable recycling of lithium resources.

Two-dimensional LiTi2(PO4)3 flakes for enhanced lithium ions battery anode

In this work, the LiTi2(PO4)3 (LTP) flakes have been prepared by employing a template method for lithium-ion batteries with high capacity. The 2D layered structure of LTP offers large aspect ratio and rich active sites, which not only create the large contact area between the electrolyte and electrode, but also promote the diffusion kinetics of Li+. As a result, the Li+ diffusion coefficient of lamellar LTP anode is 3.12 × 10-8 cm2 s-1, while it is only 5.01 × 10-10 cm2 s-1 for granular LTP anode. Further, the lamellar LTP anode delivers a high initial discharge capacity of 986.8 mAh·g-1 at 0.1 A g-1, and remains at 231.1 mAh·g-1 after 100 cycles, which is higher than that of the granular LTP anode (340.5 mAh·g-1 at 1st cycle, 169.3 mAh·g-1 at 100th cycles). Thus, the lamellar LTP should be recommended as a potential anode for high-performance LIBs due to the fast charge-discharge performance and superior cycling stability.

Recycling of the waste battery: Effect of waste battery on property of asphalt and environmental impact evaluation

A waste battery is a kind of hazardous solid waste, and traditional recycling methods can cause serious environmental pollution. In this paper, a pilot study was conducted to reduce the leaching of heavy metals in waste battery power (WBP) by using the wrapping effect of asphalt and explored the feasibility of adding waste battery as a modifier to asphalt. The main components of WBP are determined through microscopic experiments, and its compatibility with asphalt and microscopic mechanism are analyzed; The influence of WBP on asphalt properties are analyzed through routine tests and mixture tests; The leaching test of toxicity is used to analyze the impact of WBP and WBP modified asphalt on the environment. The experimental results indicate that WBP is mainly composed of MnO2, C, and ZnO; There are many wrinkles and grooves on the surface of WBP, which can effectively adsorb asphalt during the modification process, produce anchoring effect, and have good compatibility with asphalt; The components of waste battery adsorb the aging light components in asphalt through their folds and swelling, so that the proportion of heavy components is relatively increased, improving the property indicators of asphalt; From the perspective of engineering property, WBP modified asphalt mixture has strong resistance to deformation and water damage. The leaching concentration of heavy metal ions from bare WBP in soil seriously exceeded the standard. In contrast, when WBP was added to asphalt, the cumulative leaching concentration of heavy metal ions was significantly reduced due to the wrapping effect of asphalt, and the WBP leaching toxicity was greatly suppressed; The method of recycling waste battery and adding it to asphalt as a modifier can prevent the release of heavy metal ions from waste battery into the environment and reduce the risk of the total environmental harm to soil, groundwater and human health.

The Foreseeable Future of Spent Lithium-Ion Batteries: Advanced Upcycling for Toxic Electrolyte, Cathode, and Anode from Environmental and Technological Perspectives

With the rise of the new energy vehicle industry represented by Tesla and BYD, the need for lithium-ion batteries (LIBs) grows rapidly. However, owing to the limited service life of LIBs, the large-scale retirement tide of LIBs has come. The recycling of spent LIBs has become an inevitable trend of resource recovery, environmental protection, and social demand. The low added value recovery of previous LIBs mostly used traditional metal extraction, which caused environmental damage and had high cost. Beyond metal extraction, the upcycling of spent LIBs came into being. In this work, we have outlined and particularly focus on sustainable upcycling technologies of toxic electrolyte, cathode, and anode from spent LIBs. For electrolyte, whether electrolyte extraction or decomposition, restoring the original electrolyte components or decomposing them into low-carbon energy conversion is the goal of electrolyte upcycling. Direct regeneration and preparation of advanced materials are the best strategies for cathodic upcycling with the advantages of cost and energy consumption, but challenges remain in industrial practice. The regeneration of advanced graphite-based materials and battery-grade graphite shows us the prospect of regeneration of anode. Furthermore, the challenges and future development of spent LIBs upcycling are summarized and discussed from technological and environmental perspectives.

Shearing-enhanced mechanical exfoliation with mild-temperature pretreatment for cathode active material recovery from spent LIBs

The conventional approaches for recovering valuable metals from spent lithium-ion batteries (LIBs) suffer from heavy dependence on chemical reagents, high energy consumption, and low recovery efficiencies. In this study, we developed a shearing-enhanced mechanical exfoliation combined with mild-temperature pretreatment (SMEMP) method. The method achieves high-efficiency exfoliation of the cathode active materials that remain strongly adhered to polyvinylidene fluoride after it melts during mild pretreatment. The pretreatment temperature was decreased from 500-550 °C to 250 °C, the duration was decreased to 1/4-1/6 of the traditional pretreatment duration, and the exfoliation efficiency and product purity reached 96.88% and 99.93%, respectively. Despite the weakening thermal stress, the cathode materials could be exfoliated by strengthened shear forces. Compared with other traditional methods, the superiority of this method in temperature reduction and energy saving was established. The proposed SMEMP method is environmentally friendly and economical, and it offers a new route for the recovery of cathode active materials from spent LIBs.

The Recycling of Spent Lithium-Ion Batteries: Crucial Flotation for the Separation of Cathode and Anode Materials

The recycling of spent lithium-ion batteries (LIBs) has attracted great attention, mainly because of its significant impact on resource recycling and environmental protection. Currently, the processes involved in recovering valuable metals from spent LIBs have shown remarkable progress, but little attention has been paid to the effective separation of spent cathode and anode materials. Significantly, it not only can reduce the difficulty in the subsequent processing of spent cathode materials, but also contribute to the recovery of graphite. Considering the difference in their chemical properties on the surface, flotation is an effective method to separate materials, owing to its low-cost and eco-friendly characteristics. In this paper, the chemical principles of flotation separation for spent cathodes and materials from spent LIBs is summarized first. Then, the research progress in flotation separation of various spent cathode materials (LiCoO₂, LiNi_xCo_yMn_zO₂, and LiFePO₄) and graphite is summarized. Given this, the work is expected to offer the significant reviews and insights about the flotation separation for high-value recycling of spent LIBs.

Upcycling of Acid-Leaching Solutions from Li-Ion Battery Waste Treatment through the Facile Synthesis of Magnetorheological Fluid

The rapidly growing production and usage of lithium-ion batteries (LIBs) dramatically raises the number of harmful wastes. Consequently, the LIBs waste management processes, taking into account reliability, efficiency, and sustainability criteria, became a hot issue in the context of environmental protection as well as the scarcity of metal resources. In this paper, we propose for the first time a functional material—a magnetorheological fluid (MRF) from the LIBs-based liquid waste containing heavy metal ions. At first, the spent battery waste powder was treated with acid-leaching, where the post-treatment acid-leaching solution (ALS) contained heavy metal ions including cobalt. Then, ALS was used during wet co-precipitation to obtain cobalt-doped superparamagnetic iron oxide nanoparticles (SPIONs) and as an effect, the harmful liquid waste was purified from cobalt. The obtained nanoparticles were characterized with SEM, TEM, XPS, and magnetometry. Subsequently, superparamagnetic nanoparticles sized 15 nm average in diameter and magnetization saturation of about 91 emu g−1 doped with Co were used to prepare the MRF that increases the viscosity by about 300% in the presence of the 100 mT magnetic fields. We propose a facile and cost-effective way to utilize harmful ALS waste and use them in the preparation of superparamagnetic particles to be used in the magnetorheological fluid. This work describes for the first time the second life of the battery waste in the MRF and a facile way to remove the harmful ingredients from the solutions obtained after the acid leaching of LIBs as an effective end-of-life option for hydrometallurgical waste utilization.